Configurational Analysis of Thebaine, Codeine and 14β-HydroxycodeinoneN-Oxides

The 1H (400 MHz) and 13C (100 MHz) NMR peak assignments of thebaine derivatives [free base (1), hydrochloride (2 and 3), methiodide (4) and N-oxides (5 and 6)], codeine N-oxide (7) and 14β-hydroxycodeinone N-oxide (8) were performed using various one- and two-dimensional techniques. The configurations of the quaternary nitrogen-substituted alkaloids were determined. The reaction of thebaine, codeine and 14β-hydroxycodeinone with H2O2 produced thebaine N-oxide with the major product (6; Rf 0.62) having an N-CH3 axial configuration and both codeine N-oxide (7; Rf 0.40) and 14β-hydroxycodeinone N-oxide (8; Rf 0.73) with the major product having an N-CH3 equatorial configuration.